Sagot :
bonjour
f (x) = x ( x + 3 ) = x² + 3 x
f ( 2) = 2² + 2*3 = 4 + 6 = 10
f ( - 3) = 9 + 3 * -3 = 9 - 9 = 0
f ( 7) = 49 + 21 = 70
f ( - 2 ) = 4 - 2 *3 = 4 - 6 = - 2
f ( -4) = 16 + 3 * -4 = 16 - 12 = 4
Bonjour !
f(x) = x(x+3) = x² + 3x
2.a. f(-3) = -3*(-3+3) = -3*0 = 0 -> VRAI
2.b. f(7) = 7² + 3*7 = 49 + 21 = 70 -> VRAI
2.c. f(2) = 2² + 3*2 = 4 + 6 = 10 ≠ 7 -> FAUX
2.d. f(-4) = (-4)² + 3*(-4) = 16 - 12 = 4 -> VRAI
N'hésite pas si tu as une question :)